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The development of ciprofloxacin resistance in Pseudomonas aeruginosa involves multiple response stages and multiple proteins.

ABSTRACT: Microbes have developed resistance to nearly every antibiotic, yet the steps leading to drug resistance remain unclear. Here we report a multistage process by which Pseudomonas aeruginosa acquires drug resistance following exposure to ciprofloxacin at levels ranging from 0.5× to 8× the initial MIC. In stage I, susceptible cells are killed en masse by the exposure. In stage II, a small, slow to nongrowing population survives antibiotic exposure that does not exhibit significantly increased resistance according to the MIC measure. In stage III, exhibited at 0.5× to 4× the MIC, a growing population emerges to reconstitute the population, and these cells display heritable increases in drug resistance of up to 50 times the original level. We studied the stage III cells by proteomic methods to uncover differences in the regulatory pathways that are involved in this phenotype, revealing upregulation of phosphorylation on two proteins, succinate-semialdehyde dehydrogenase (SSADH) and methylmalonate-semialdehyde dehydrogenase (MMSADH), and also revealing upregulation of a highly conserved protein of unknown function. Transposon disruption in the encoding genes for each of these targets substantially dampened the ability of cells to develop the stage III phenotype. Considering these results in combination with computational models of resistance and genomic sequencing results, we postulate that stage III heritable resistance develops from a combination of both genomic mutations and modulation of one or more preexisting cellular pathways.

SUBMITTER: Su HC

PROVIDER: S-EPMC2976116 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature

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The development of ciprofloxacin resistance in Pseudomonas aeruginosa involves multiple response stages and multiple proteins.

Su Hsun-Cheng HC Ramkissoon Kevin K Doolittle Janet J Clark Martha M Khatun Jainab J Secrest Ashley A Wolfgang Matthew C MC Giddings Morgan C MC

Antimicrobial agents and chemotherapy 20100809 11

Microbes have developed resistance to nearly every antibiotic, yet the steps leading to drug resistance remain unclear. Here we report a multistage process by which Pseudomonas aeruginosa acquires drug resistance following exposure to ciprofloxacin at levels ranging from 0.5× to 8× the initial MIC. In stage I, susceptible cells are killed en masse by the exposure. In stage II, a small, slow to nongrowing population survives antibiotic exposure that does not exhibit significantly increased resist ...[more]

PMID: 20696867

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Project description:Factor for inversion stimulation (Fis) is a versatile DNA binding protein that plays an important role in coordinating bacterial global gene expression in response to growth phases and environmental stresses. Previously, we demonstrated that Fis regulates the type III secretion system (T3SS) in Pseudomonas aeruginosa In this study, we explored the role of Fis in the antibiotic resistance of P. aeruginosa and found that mutation of the fis gene increases the bacterial susceptibility to ciprofloxacin. We further demonstrated that genes related to pyocin biosynthesis are upregulated in the fis mutant. The pyocins are produced in response to genotoxic agents, including ciprofloxacin, and the release of pyocins results in lysis of the producer cell. Thus, pyocin biosynthesis genes sensitize P. aeruginosa to ciprofloxacin. We found that PrtN, the positive regulator of the pyocin biosynthesis genes, is upregulated in the fis mutant. Genetic experiments and electrophoretic mobility shift assays revealed that Fis directly binds to the promoter region of prtN and represses its expression. Therefore, our results revealed novel Fis-mediated regulation on pyocin production and bacterial resistance to ciprofloxacin in P. aeruginosaIMPORTANCEPseudomonas aeruginosa is an important opportunistic pathogenic bacterium that causes various acute and chronic infections in human, especially in patients with compromised immunity, cystic fibrosis (CF), and/or severe burn wounds. About 60% of cystic fibrosis patients have a chronic respiratory infection caused by P. aeruginosa The bacterium is intrinsically highly resistant to antibiotics, which greatly increases difficulties in clinical treatment. Therefore, it is critical to understand the mechanisms and the regulatory pathways that are involved in antibiotic resistance. In this study, we elucidated a novel regulatory pathway that controls the bacterial resistance to fluoroquinolone antibiotics, which enhances our understanding of how P. aeruginosa responds to ciprofloxacin.

Dataset Information

The development of ciprofloxacin resistance in Pseudomonas aeruginosa involves multiple response stages and multiple proteins.

Publications

The development of ciprofloxacin resistance in Pseudomonas aeruginosa involves multiple response stages and multiple proteins.

Similar Datasets

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